U.S. patent application number 14/694612 was filed with the patent office on 2015-10-29 for lens driving apparatus, lens barrel and optical apparatus.
The applicant listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Koji Sato.
Application Number | 20150309388 14/694612 |
Document ID | / |
Family ID | 54334642 |
Filed Date | 2015-10-29 |
United States Patent
Application |
20150309388 |
Kind Code |
A1 |
Sato; Koji |
October 29, 2015 |
LENS DRIVING APPARATUS, LENS BARREL AND OPTICAL APPARATUS
Abstract
The lens driving apparatus includes a lens holding member that
holds lens; a rack provided in the lens holding member transmits a
motor driving force to the lens holding member; a first guide part
that supports the lens holding member to be movable back and forth
in an optical axis direction of the optical lens; a second guide
part that supports the lens holding part to be movable as a first
guide part, farther separated from the rack than the first guide
part in a direction orthogonal to the optical axis direction; both
contact parts in the lens holding part, with which both guide parts
respectively are in contact; and an energizing part that energizes
the second contact part at a position separated in the longitudinal
direction of the second guide part so as to be in contact with the
second guide part.
Inventors: |
Sato; Koji; (Utsunomiya-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
|
JP |
|
|
Family ID: |
54334642 |
Appl. No.: |
14/694612 |
Filed: |
April 23, 2015 |
Current U.S.
Class: |
396/85 ;
359/823 |
Current CPC
Class: |
G02B 7/04 20130101; G03B
3/10 20130101; G03B 13/34 20130101 |
International
Class: |
G03B 13/34 20060101
G03B013/34; G02B 7/04 20060101 G02B007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2014 |
JP |
2014-092366 |
Claims
1. A lens driving apparatus comprising: a lens holding member that
holds an optical lens; a rack provided in the lens holding member
and that transmits a motor driving force to the lens holding
member; a first guide part that supports the lens holding member so
as to be movable back and forth in an optical axis direction of the
optical lens; a second guide part that supports the lens holding
member so as to be movable back and forth in the optical axis
direction, farther separated from the rack than the first guide
part in a direction orthogonal to the optical axis direction; a
first contact part and a second contact part provided in the lens
holding member, with which the first guide part and the second
guide part respectively are in contact; and an energizing member
that energizes the second contact part at a position separated in
the longitudinal direction of the second guide part so as to be in
contact with the second guide part.
2. The lens driving apparatus according to claim 1, wherein the
second contact part is a rotation regulating part that regulates a
rotation of the lens holding member in a direction orthogonal to
the optical axis direction.
3. The lens driving apparatus according to claim 1, wherein the
energizing member that generates an energizing force in normal
direction of a contact surface between the second contact part and
the second guide part.
4. The lens driving apparatus according to claim 1, wherein the
lens holding member is energized so as to be tilted toward the
first guide part by using the second contact part as a fulcrum.
5. The lens driving apparatus according to claim 1, wherein the
energizing member energizes the second contact part toward the
second guide part and both ends of two openings serving as the
first contact part are respectively energized in a direction
orthogonal to an optical axis direction with respect to the first
guide part and in respectively opposing directions.
6. The lens driving apparatus according to claim 1, wherein the
energizing member is configured by an elastic material.
7. The lens driving apparatus according to claim 1, wherein the
energizing member is configured by a magnetic material.
8. A lens barrel comprising: a lens group; and a lens driving
apparatus that moves the lens group in an optical axis direction,
wherein the lens driving apparatus comprises: a lens holding member
that holds an optical lens; a rack provided in the lens holding
member and that transmits a motor driving force to the lens holding
member; a first guide part that supports the lens holding member so
as to be movable back and forth in an optical axis direction of the
optical lens; a second guide part that supports the lens holding
member so as to be movable back and forth in the optical axis
direction, farther separated from the rack than the first guide
part in a direction orthogonal to the optical axis direction; a
first contact part and a second contact part provided in the lens
holding member, with which the first guide part and the second
guide part respectively are in contact; and an energizing member
that energizes the second contact part at a position separated in
the longitudinal direction of the second guide part so as to be in
contact with the second guide part.
9. An optical apparatus comprising: a camera; and a lens barrel
which is demountable from the camera and has a lens group; and a
lens driving apparatus that moves the lens group in an optical axis
direction, wherein the lens driving apparatus comprises: a lens
holding member that holds an optical lens; a rack provided in the
lens holding member and that transmits a motor driving force to the
lens holding member; a first guide part that supports the lens
holding member so as to be movable back and forth in an optical
axis direction of the optical lens; a second guide part that
supports the lens holding member so as to be movable back and forth
in the optical axis direction, farther separated from the rack than
the first guide part in a direction orthogonal to the optical axis
direction; a first contact part and a second contact part provided
in the lens holding member, with which the first guide part and the
second guide part respectively are in contact; and an energizing
member that energizes the second contact part at a position
separated in the longitudinal direction of the second guide part so
as to be in contact with the second guide part.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a lens driving apparatus, a
lens barrel, and an optical apparatus.
[0003] 2. Description of the Related Art
[0004] Conventionally, a lens driving apparatus that moves a lens
group by using a stepping motor when performing a variable power
operation and a focusing operation has been mounted on a lens
barrel used as an interchangeable lens or the like in an optical
apparatus, for example, a digital still camera and a video camera.
Such a lens driving apparatus that moves a guide that guides a
movement of the lens during moving back and forth of the lens and a
lens holding frame without a wobble between them is desired.
Japanese Patent Application Publication No. 6-174992 discloses a
configuration in which a regulation of a rotation blur is achieved
by a rack configuration that has interposing teeth that interpose a
motor screw in a rack. Additionally, Japanese Patent Application
Publication No. 2007-298718 discloses a configuration in which the
regulation of the rotation blur is achieved by a configuration in
which the rack is pressed against the motor screw.
[0005] However, in the conventional arts disclosed in the
aforementioned patent documents, there is a possibility that a
stable balance cannot be configured when, for example, an attitude
is changed in a case where the mass of the lens group is large,
thereby to cause a tilt of the lens group and the rotation blur.
Additionally, it may affect an optical property, for example, an
image shake, as a result. For example, Japanese Patent Application
Publication No. 6-174992 discloses a configuration in which the
interposing teeth that interpose the motor screw are provided in
the rack, an angle is given to the interposing teeth, and an
energizing force is applied to the lens group. Here, it is
necessary to increase an interposing force or increase the angle of
the interposing teeth in order to increase the energizing force to
correspond to the mass of the lens group. Accordingly, there is a
problem in which a load that obstructs the rotation of the motor
becomes high in many cases. Although the disclosure of Japanese
Patent Application Publication No. 2007-298718 enables decreasing
the load to the motor compared with the disclosure of Japanese
Patent Application Publication No. 6-174992, both disclosures
require increasing the energizing force of the rack according to
the increase of the mass of the lens group, and thus, it is
difficult to avoid the similar problem to be solved.
SUMMARY OF THE INVENTION
[0006] The present invention provides, for example, a lens driving
apparatus and the like that enables stably energizing a lens group
without increasing the rotation load of a motor and controlling an
unintended tilt and a rotation blur.
[0007] A lens driving apparatus in the present invention includes a
lens holding member that holds an optical lens; a rack provided in
the lens holding member and that transmits a motor driving force to
the lens holding member; a first guide part that supports the lens
holding member so as to be movable back and forth in an optical
axis direction of the optical lens; a second guide part that
supports the lens holding member so as to be movable back and forth
in the optical axis direction, farther separated from the rack than
the first guide part in a direction orthogonal to the optical axis
direction; a first contact part and a second contact part provided
in the lens holding member, with which the first guide part and the
second guide part respectively are in contact; and an energizing
member that energizes the second contact part at a position
separated in the longitudinal direction of the second guide part so
as to be in contact with the second guide part.
[0008] Further features of the present invention will become
apparent from the following description of exemplary embodiments
with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an exploded perspective view that illustrates a
configuration of a lens barrel that can mount a lens driving
apparatus according to first embodiment of the present
invention.
[0010] FIG. 2 is a perspective view that illustrates a
configuration of the lens driving apparatus according to the first
embodiment.
[0011] FIG. 3A is a side view of an explanatory view that explains
the operation of the lens driving apparatus according to the first
embodiment.
[0012] FIG. 3B is a front view of the explanatory view that
explains the operation of the lens driving apparatus according to
the first embodiment.
[0013] FIG. 4 is a perspective view that illustrates a
configuration of the lens driving apparatus according to second
embodiment of the present invention.
[0014] FIG. 5A is a side view of an explanatory view that explains
the operation of the lens driving apparatus according to the second
embodiment.
[0015] FIG. 5B is a front view of the explanatory view that
explains the operation of the lens driving apparatus according to
the second embodiment.
DESCRIPTION OF THE EMBODIMENTS
[0016] Hereinafter, the embodiments of the present invention will
be described with reference to drawings and the like.
First Embodiment
[0017] First, a description will be given of a lens barrel (lens
device) that can mount a lens driving apparatus according to first
embodiment of the present invention. FIG. 1 is an exploded
perspective view that illustrates a configuration of a lens barrel
according to first embodiment, and a fixed cylinder that fixes each
of components is not illustrated for the purpose of simplifying the
description. The lens barrel according to the present embodiment is
an interchangeable lens that is attachable to and detachable from
an image capturing apparatus (optical apparatus), for example, a
digital still camera provided with an imaging element or a still
camera using a silver film, in one example. However, the lens
barrel according to the present embodiment may be one that is
incorporated in the image capturing apparatus, not limited to being
incorporated in the image capturing apparatus, and it may be, for
example, an interchangeable lens that is attachable to and
detachable from a projection device such as a projector, or it may
be one that is incorporated in the projection device. As shown in
FIG. 1, the lens barrel includes an optical lens group 1, a
variable power lens group 2, a focus comparison lens group 3, a
focusing lens group 4, and a holder 13, and photographing is
allowed by placing an imaging element (not illustrated) at the rear
of the holder 13.
[0018] Next, a description will be given of the lens driving
apparatus that moves the lens group in an optical axis direction K.
FIG. 2 is a perspective view that illustrates a configuration of
the lens driving apparatus according to the present embodiment.
Here, a case in which the aforementioned focusing lens group is
driven is given as an example. Such a lens driving apparatus
includes the focusing lens group 4, a rack (rack member) 10, a
guide bar (first guide part), a guide bar 12 (second guide part),
and a spring 14 (energizing member, elastic material).
Additionally, the focusing lens group 4 includes a lens L and a
lens holding frame (lens holding member) 4g that holds the lens.
The rack 10 is attached to the lens holding frame 4g, engaged with
a screw part of a motor 9, transmits the rotation of the motor 9
(motor driving force) to the lens holding frame 4g, and thus, the
focusing lens group 4 can be driven back and forth in the optical
axis direction K. The lens holding frame 4g is provided with a
sleeve hole (opening, first contact part) 4a and a sleeve hole
(opening, first contact part) 4b that are in contact with a guide
bar 11 to guide it and it is held (supported) so as to be movable
back and forth by the guide bar 11 in the optical axis direction K.
A rotation regulating part (rotation regulating groove, second
contact part) 4c interposes (is in contact with) a guide bar 12 and
has the function of regulating a position of the lens holding frame
4g in a rotation direction orthogonal to the optical axis direction
K, and a function to regulate a rotation blur that occurs during
moving back and forth of the lens holding frame 4g. The guide bar
12 holds the lens holding frame 4g so as to be movably back and
forth in the optical axis direction K, and it is farther separated
from the rack 10 than the guide bar 11 in the direction orthogonal
to the optical axis direction K. The spring 14 is a torsion spring
attached around a spring hanging part 4e having a substantially
cylindrical shape, which is provided at the lens holding frame 4g.
One end of the spring 14 is held at a spring receiving groove 4f
provided in a spring receiving part 4d and the other end thereof is
positioned by being hooked on the guide bar 12, and an energizing
force is generated between the lens holding frame 4g and the guide
bar 12.
[0019] A detailed description will be given of the operation of
such lens driving apparatus with reference to FIGS. 3A and 3B.
FIGS. 3A and 3B are explanatory views that explain the operation of
the lens driving apparatus according to the present embodiment,
FIG. 3A is a side view and FIG. 3B is a front view. As shown in
FIGS. 3A and 3B, the spring 14 can generate an energizing force A
between the spring receiving groove 4f provided in the lens holding
frame 4g and the guide bar 12. In other words, the spring 14 can
generate an energizing force A in normal direction of a contact
surface between the rotation regulating part 4c and the guide bar
12. A force to depress the lens holding frame 4g generated by the
energizing force A functions as an energizing force to press the
rotation regulating part 4c and the guide bar 12. Although the
rotation regulating part 4c has a force to depress the guide bar 12
by the energizing force B, both ends of the guide bar 12 are
attached and supported by a receiving part (not illustrated), and
thus the position of the guide bar 12 does not change and a
counterforce B' is generated. As shown in FIG. 3A, the energizing
force A applied by the spring 14 is generated at a position
separated from the rotation regulating part 4c in a longitudinal
direction of the guide bar 12 (the energizing force A shifts to
right side in the drawing). Accordingly, the energizing force A
includes a force to rotate the lens holding frame 4g in the
clockwise direction around the rotation regulating part 4c in the
drawing. In other words, the lens holding frame 4g is energized so
as to be tilted toward the guide bar 11 by using the rotation
regulating part 4c as a fulcrum. This force generates an energizing
force C in a lifting direction at the sleeve hole 4a and generates
an energizing force D in a depressing direction at the sleeve hole
4b, and the lens holding frame 4g can be pressed by each of the
energizing forces with respect to the guide bar 11 without the
wobble. Moreover, the position of the guide bar 11 is not changed
by the energizing forces C and D of the lens holding frame 4g
because it is held by a fixed cylinder (not illustrated).
Accordingly, the counterforce C' is generated at the sleeve hole 4a
and the counterforce D' is generated at the sleeve hole 4b, whereby
the position is held by a balance occurring between the
counterforces B', C', D' and the energizing force A. As mentioned
above, the sleeve hole 4a, the sleeve hole 4b, and the rotation
regulating part 4c are each held with the energizing forces,
whereby they can be energized without adding a particular
energizing force from the rack 10.
[0020] As described above, it is possible to separately set the
energizing force needed to regulate the rotation blur of the lens
holding frame 4g and the energizing force to press the rack 10 to
the motor screw, according to the present embodiment. Therefore,
the rotation blur of the lens group can be regulated without
increasing a rotation load of the motor. Additionally, this lens
driving apparatus allows providing the lens barrel and the optical
apparatus that cause almost no the image shake or the like and that
have an excellent optical performance.
Second Embodiment
[0021] Next, a description will be given of the lens driving
apparatus according to second embodiment of the present invention.
Although a spring is used as the energizing member in the first
embodiment, the lens driving apparatus according to the present
embodiment differs from the first embodiment in that a magnet (Mg,
magnetic material) is used as the energizing member. Note that, a
configuration of the lens barrel itself in the present embodiment
is basically similar to that in the first embodiment, and except
for the parts related to the lens driving apparatus, the detailed
description is omitted.
[0022] Here, a description will be given of a configuration of the
lens driving apparatus according to the second embodiment of the
present invention with reference to FIG. 4. The lens driving
apparatus of the present embodiment includes the focusing lens
group 4, the rack 10, the guide bar 11 (first guide part), the
guide bar (second guide part), and a magnet 15 (energizing member,
magnetic material). Note that, the same reference numerals are
provided to the components that are the same as the components in
the configurations as those in the first embodiment, and detailed
description of those components are omitted. The magnet 15 is
integrally held with respect to a magnet receiving part 40d
provided in the lens holding frame 4g, and has a magnetic
attracting force between the guide bar 12 and itself.
[0023] A detailed description will be given of the operation of
such a lens driving apparatus with reference to FIGS. 5A and 5B.
FIGS. 5A and 5B are explanatory views that explain the operation of
the lens driving apparatus according to the second embodiment, FIG.
5A is a side view and FIG. 5B is a front view. As shown in FIGS. 5A
and 5B, the magnet 15 is integrally held by the lens holding frame
4g and the magnetic attracting force occurring between the magnet
15, and the guide bar 12 generates an energizing force E. A force
to depress the lens holding frame 4g generated by the energizing
force E functions as an energizing force F between the rotation
regulating part 4c and the guide bar 12. Although the rotation
regulating part 4c has a force that depresses the guide bar 12 by
the energizing force F, the both ends of the guide bar 12 are
attached and supported by the receiving part (not illustrated),
whereby the position of the guide bar 12 does not change and a
counterforce F' is generated. As shown in FIG. 5A, the energizing
force E applied by the magnet 15 is generated at a position
separated from the rotation regulating part 4c in a longitudinal
direction of the guide bar 12 (the energizing force E is offset to
the right side in the drawing). Accordingly, the energizing force E
includes a force that rotates the focusing lens group 4 in the
clockwise direction around the rotation regulating part 4c in the
drawing. This force generates an energizing force G in a lifting
direction at the sleeve hole 4a and generates an energizing force H
in a depressing direction, which is a direction opposite to that of
the energizing force G, at the sleeve hole 4b, and the lens holding
frame 4g can be pressed with each of the energizing forces with
respect to the guide bar 11 without the wobble. Moreover, the
position of the guide bar 11 is not changed by the energizing
forces G, H of the lens holding frame 4g because it is held by the
fixed cylinder (not illustrated). Accordingly, the counterforce G'
is generated at the sleeve hole 4a, the counterforce H' is
generated at the sleeve hole 4b, and the position is held by a
balance that occurs between the counterforce F', G', H' and the
energizing force E. As disclosed above, the sleeve hole 4a, the
sleeve hole 4b, and the rotation regulating part 4c are each held
by the energizing forces, whereby they can be energized without
adding a particular energizing force from the rack 10.
[0024] As described above, according to the present embodiment, it
is possible to separately set the energizing force needed to
regulate the rotation blur of the lens holding frame 4g and the
energizing force to press the rack 10 against the motor screw, in a
manner similar to the first embodiment. Accordingly, the rotation
blur of the lens group can be regulated without increasing the
rotation load of the motor. Note that a case in which the magnet as
the energizing member is provided on the guide bar 12 (regulating
the clockwise rotation) is described in the present embodiment, but
the present invention is not limited to this and the magnet may be
provided under the guide bar 12.
[0025] Note that a case in which the focusing lens group is driven
is described in the first and the second embodiments, but the
present invention is not limited to this, and a case in which
another lens group, for example, a variable power lens group is
driven is allowed.
[0026] While the present invention has been described with
reference to exemplary embodiments, it is to be understood that the
invention is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0027] This application claims the benefit of Japanese Patent
Application No. 2014-092366 filed Apr. 28, 2014, which is hereby
incorporated by reference herein in its entirety.
* * * * *